Acetylcholinesterase (AChE), the enzyme that terminates cholinergic transmission in the nervous system, is the target of nerve agents and organophosphate pesticides. Inactivation of AChE can result in rapid debilitation or death, thus the use of easily synthesized AChE inactivating nerve agents such as soman and sarin by terrorists looms as a potential catastrophic event. We have previously shown that about 80% of the newly-synthesized AChE molecules are catalytically inactive and subsequently degraded in the endoplasmic reticulum. In addition, while studying the assembly of the multimeric enzyme, we discovered that the noncatalytic subunit appears to "rescue" the catalytic subunits from degradation and, moreover, stabilizes the tetramers for subsequent transport to the muscle cell surface and secretion. Based on these observations we have designed and tested peptides that can mimic the ability of the non-catalytic subunits to rescue the enzyme and increase its expression. Our specific aims on this project are;1) test the hypothesis that the non-catalytic subunit of AChE increases expression of the enzyme by rescuing the catalytic subunits from degradation. The objective is to determine the molecular mechanisms underlying the observed increase in AChE expression to develop more effective inducing peptides;2) Optimize the synthetic peptides designed to rescue AChE for their cellular uptake and retention as well as ability to induce tetramerization and increased enzyme stability;3) Test the ability of the non-catalytic AChE subunit mimetic peptides to increase AChE expression in vivo using a mouse model;and 4) Determine the ability of the synthetic peptides to protect mice from exposure to organophosphate nerve agents and/or to improve survival when administered after exposure. Together these studies could lead to a novel method for increasing AChE expression in vivo for protection against organophosphate compounds as well as enhancing the rate of recovery following exposure.